A term to describe a situation where fan girls start spazzing and going crazy over new videos of Jay Park of AOM. A few symptoms include: screaming until throat hurts, lack of sleep from watching his videos over and over again, stalking his fan sites for new pictures, excessive drooling, and etc. Might lead to a heart attack if the Jay Fever takes off his shirt to show his 12 pack.

TeamJay: I caught the Jay fever on April 3rd of 2010 when Jay danced to Single Ladies.
Misadoan - I'm sick, I caught the Jayfever...mom can I stay home on Monday?
tranling- h1n1 step aside , cuz a new flu goes by the name Jay Park is here n guarantee u that once u caught it , there's no cure at all lol